Similarities asks how two words are alike
The WAIS Similarities subtest presents two words and asks how they are alike. A strong answer brings both under a shared higher-order concept rather than describing one word or naming a situation that happens to involve both.
In WAIS-IV, Similarities is a core subtest of the Verbal Comprehension Index (VCI). In WAIS-5, it remains a primary VCI subtest and contributes to FSIQ.
Two things can share their appearance, the setting in which they are used, their purpose, or a broader category. Similarities looks for the concept that best captures the central meaning of both, rather than a feature they happen to share.
For a non-test example, consider a map app and a public-transport journey planner. Saying that both are used on a smartphone identifies a surface similarity. Describing both as sources of information used to plan a route captures their central function in one concept.
The quality of the relationship matters more than unusually abstract vocabulary or a long answer.
What higher and lower Similarities scores can show
A higher score indicates strength in identifying and expressing the essential relationship between concepts. A lower score means that answers more often remained at the level of concrete features or situations, or that the shared idea was recognised but not expressed clearly enough. The same abstraction is useful when summarising an argument, grouping cases, or identifying the shared issue across several examples.
If Similarities is lower than Vocabulary, forming the relationship was more demanding than defining individual words. If both are low, access to precise word meanings may be contributing before the comparison is made. If Similarities is lower than Information, identifying a relationship between familiar meanings was more demanding than retrieving facts.
How to read WAIS results explains how to place a subtest difference within the complete score profile.
How Similarities differs from Vocabulary and Information
Similarities, Vocabulary, and Information all draw on acquired language and semantic knowledge. They differ in what the person must do with that knowledge.
| Subtest | Direct task | Main processing involved |
|---|---|---|
| Similarities | Explain what two words have in common | Comparing concepts, generating a shared relationship, and verbal abstract reasoning |
| Vocabulary | Explain the meaning of one word | Retrieving vocabulary, distinguishing precise meanings, and verbal expression |
| Information | Answer a question about a general fact | Retrieving acquired general knowledge |
Together, the three tasks separate defining a meaning, retrieving a fact, and reorganising meanings into a relationship.
Similarities and BrainTypeIQ Analogies share relational reasoning in different formats
BrainTypeIQ Analogies presents an example word pair, asks the person to identify its relationship, and then requires them to choose another pair with the same relationship. Like WAIS Similarities, it goes beyond the individual meanings of the words and asks how concepts are related.
WAIS requires an open spoken explanation. BrainTypeIQ uses a selection format, reducing the demand of composing an answer and focusing on recognising a relationship pattern and applying it to another pair. The tasks differ, but both test whether the person can move beyond individual words to the relationship between them.